Pages

Wednesday, May 8, 2013

Tutorial: GrADS Hovmöller diagram

Hovmöller diagrams are very useful for determining the speed of various atmospheric disturbances, as it contours a variable in both time and space. Typically, the spatial variable is on the x-axis and the time variable on the y-axis.

It's very easy to plot a simple Hovmöller diagram in GrADS. To do this, you only need to set your varying dimensions to longitude and time. The axes will arrange longitude on x, and time on y. In this tutorial, the example will be a Hovmöller diagram of 500mb meridonal wind from the GFS model. The block of code below will set up and plot this data.

6 comments:

Hi thanks for your tutorials those are very useful for me. I was wondering if I can do a hovmoeller diagram with adiagonal cross section, because I've had some trouble trying to make a plot for that in a cross section of the coastal line. I do Know making hov. graphics on a straight line way,though, in a diagonal way another history. Thanks in advance.

You could probably get this to work by using the grid2stn and coll2grid functions, these functions essentially allow you to take gridded data from grads at a set lat/lon point and organize them into a grid, so you could take points along your diagonal, or coastline and then do a hovmuller using these points.

I have a tutorial on how to do this for an arbitrary cross section, I think you could modify these to work for a time/distance plot as well.

Thank you so much for answering me quickly. I checked out your advice, but I am still having some trouble since it does not permit a time/distance section plot with a cross section. I do know that those kinds of plots are easily done by using Matlab or GMT, but personally speaking I do prefer using GrADS. I'll be looking forward to seeing more information about.